Recently, it was reported that "...approximately 2 million American adults have disorders of taste and smell. For 1975 and 1976 combined, a chemosensory problem was the major presenting symptom in approximately 435,000 visits to a physician's office." Prior to establishing any successful clinical program, much remains to be learned about the basic mechanisms of chemoreception. Our research program has used genetic and behavioral genetic methods in studies of individual differences in olfaction in an effort to provide models for future investigations. Many people with otherwise intact olfactory capabilities cannot smell some substances. In previous studies of odor blindness to androstenone, an odorous steroid, we found that the inability to perceive an odor is inherited, as evidenced by the results of a twin study. Pilot work suggested that developmental factors and environmental exposures may influence or alter perception of the odor of androstenone. Based on these findings, we propose i) to determine the mode of transmission of odor blindness to androstenone by conducting family pedigree analyses, ii) to determine the role of developmental factors in the perception of androstenone by testing children and adults of different ages, and iii) to attempt to alter individual sensitivity to this odorant by long-term exposure to androstenone. These studies will produce fundamental information on human olfaction. They will provide an integrated study of factors (genetic, developmental, experimential) which may influence sensitivity to a particular odor. The data obtained can be used as a foundation for future investigations and may set the stage for studies using the techniques of modern neurobiology to determine the factors responsible for differences between those who perceive androstenone and those who cannot.